Revert "Adding documentation on the ISSO_CORS_ORIGIN env variable - close #407"
Revert "Adding documentation on the ISSO_CORS_ORIGIN env variable - close #407"

This reverts commit b73255ec2e019445dc46a794c4ad56af3db26403.

Reason for revert: This feature never worked.
See discussion in https://github.com/posativ/isso/issues/720

posativ/isso,posativ/isso,posativ/isso,posativ/isso